Electronvolts (eV)

The electronvolt is the energy an electron gains when accelerated through one volt, exactly 1.602176634 × 10⁻¹⁹ joules.

Convert electronvolts to any energy unit

1 electronvolt = 1.6021766 × 10-19 joules

Quick facts

Unit
Electronvolt (plural: electronvolts)
Symbol
eV
Measures
Energy / Work / Heat
System
Atomic & physics
Equals
1.6021766 × 10-19 joules
Definition
Exactly 1.602176634 × 10⁻¹⁹ J.
Also written
electron volt

1 electronvolt in other units

Joules1.6021766 × 10-19 J
Kilocalories3.8292941 × 10-23 kcal
Kilowatt-hours4.4504906 × 10-26 kWh
British thermal units1.5185704 × 10-22 BTU
Calories3.8292941 × 10-20 cal
Kilojoules1.6021766 × 10-22 kJ
Calories (food)3.8292941 × 10-23 Cal
Watt-hours4.4504906 × 10-23 Wh

What is an electronvolt?

The electronvolt is the energy an electron gains when accelerated through one volt, exactly 1.602176634 × 10⁻¹⁹ joules. It is the natural unit of atomic, nuclear and particle physics: chemical bonds are a few eV, visible light photons 1.6–3.3 eV and the Large Hadron Collider collides protons at 13.6 TeV.

Where the electronvolt sits among energy units

The electronvolt is number 7 of 99 on our scale of energy units, ordered from smallest to largest.

Wavenumber (energy)1 eV = 8,065.54 cm⁻¹ Millielectronvolt1 eV = 1,000 meV Kilojoule per mole1 eV = 96.4853 kJ/mol Kilocalorie per mole1 eV = 23.0605 kcal/mol Electronvoltthis unit Megaelectronvolt1 MeV = 1,000,000 eV Erg1 erg = 624,151,000,000 eV Joule1 J = 6.241509 × 1018 eV Foot-pound1 ft⋅lbf = 8.46235 × 1018 eV

What electronvolts are used for

  • Photon energies and semiconductor band gaps
  • Nuclear and particle physics (MeV, GeV, TeV)
  • Ionization energies in chemistry

Electronvolts in real life

  • Silicon's band gap is 1.12 eV
  • A green light photon has about 2.3 eV
  • Ionizing a hydrogen atom takes 13.6 eV
  • A uranium fission releases about 200 MeV

Top electronvolt conversions

Common amounts of electronvolts

Convert electronvolts to all 98 other units

Metric (SI)

Electrical

Calories

BTU & therms

Mechanical

Atomic & physics

Fuel & explosive equivalents

Everyday comparisons

Convert to electronvolts

Frequently asked questions

What is an electronvolt?

The electronvolt is the energy an electron gains when accelerated through one volt, exactly 1.602176634 × 10⁻¹⁹ joules.

How is the electronvolt defined?

Exactly 1.602176634 × 10⁻¹⁹ J.

How many joules are in an electronvolt?

One electronvolt equals 1.6021766e-19 joules.

How many kilocalories are in an electronvolt?

One electronvolt equals 3.8292941e-23 kilocalories.

How many kilowatt-hours are in an electronvolt?

One electronvolt equals 4.4504906e-26 kilowatt-hours.